Vegetable family grouping for rotational purposes:

A vegetable rotation plan should be used when deciding where to plant vegetables. Vegetable crop rotation is the key to long term success in vegetable gardening. Failure to rotate crops annually will result in increased soil borne disease, nematodes, soil insects, imbalance of essential mineral elements, and a dramatic decline in productivity. Crop rotation is the most economical ways to aid in prevention and control of insects and disease. Vegetables in the same family grouping are likely to be susceptible to the same  diseases and  organisms. Rotate these groups so vegetables from one group are not planted in the same location more than once every 3 to 5 years. I Have my garden equally divided into 6 section. I plant based on the grouping table below. I simply rotate all groups clockwise in the beds each season. I grow groups A through E in Spring, Summer and group F in the winter. In winter I grow nitrogen fixing  crops in my empty beds or cover them with leaf mulch until spring.